Gigabyte 7970 Ghz cooling issues / watercool?

[demosthenez]

 
tl;dr Gaming/Mining rig: Should I

• a) watercool 2 x Gigabyte 7970 Ghz WF, and apply heatsinks to the VRM/RAM; or
• b) swap for reference Diamond 7970 with full waterblocks?

Have updated my gaming rig to include 2 x Gigabyte 7970 Ghz edition cards - figured if I could get them mining, I may pay off the card cost within a few months (or at least get a few coins in my wallet).

Have a serious issue with cooling these.
They are in an Antec 900 case, with the following fans:

• 2 x 120mm inlet fans on the front
• 1 x 120mm inlet on the side (almost directly onto the GPU)
• 1 x 120mm exhaust out the back
• 1 x 200mm exhaust on top

Was running them in cgminer with the "-150" memdiff setting, until I discovered MSI AB could clock the memory right down (mining BTC).

At 1175/380 I can get one card by itself sitting nicely at around 72c, with the case side on, all case fans full.
When both cards are running, the temps will keep climbing until cgminer starts throttling. With cgminer throttling off, I'd be above 90c.
I can stabilise them to around 80c with the case side off, and a Honeywell desk fan blowing directly onto the cards. (Ambient temps are pretty warm in the study now though)

Since this is a general work/gaming PC as well, I'd rather not have the noise of the desk fan (plus, guest room is next door - very low WAF with the noise).

Have been contemplating a watercooled setup, but am cautious of using a generic GPU block for these while mining. Have heard that mining can put some serious load onto the VRM's, and without active cooling they'd get pretty hot.

The v2.1 Gigabyte cards do not have temp sensors on the VRM's, so I'd have no idea if the general case airflow is enough to cool these down while mining.

Has anyone had any experience watercooling these cards? Will I need to install fans over the VRM heatsinks (I'd install aftermarket heatsinks)?
I've contemplated swapping these out for some reference 7970's, and I'd get a full cover waterblock. My only hesitation would be if there is anything I'd be giving up by replacing the Gigabytes - would assume that the updated GB PCB's would be more stable than the reference PCB's, and generally easier to get sitting at the high clock speeds I want. Is this correct?

(Ignore the cost inefficiencies with water cooling - its not a dedicated miner, and I'm okay with spending a bit on reducing the noise)

Thanks.

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[piit79]

You're facing a difficult decision Not quite sure you can air cool the two 7970 in a closed case due to the way the heatsinks are constructed - hot air stays in the case.

Watercooling may be the best way to go. If you do decide to watercool, make sure to get 7970-specific full-cover waterblocks - they will be more expensive but will cover the whole card including VRMs.

Before I had my rigs in an airconditioned server room I decided to watercool main main rig - 3x 5970 + 1x 5870 (2.5 Gh/s). It was my first experience with watercooling and it was fun.

[frejo]

I think you're better of getting a pci-e riser and putting one of the cards outside the case, cheapest and easiest solution imo

[demosthenez]

I think you're better of getting a pci-e riser and putting one of the cards outside the case, cheapest and easiest solution imo

Interesting idea, unfortunately the room doubles as my study - and I'd prefer the aesthetics of a closed case.

Though I did just throw together a quick shopping cart at FrozenCPU - starting to realise that my ROI may blow completely out if I go down this path.

[computerparts]

The Antec 900 isn't exactly the best case for air cooling multiple gpu setups. You would have been better off with a HAF-X, possibly a HAF-XB, DF-85, or even a Phantom. The key is air flow and fan placement, not the number of fans. Water cooling gets expensive as I'm sure you have already figured out.

[ISAWHIM]

Does your PSU blow out, or suck-in?

What other fans do you have running inside your case? Are they blowing in or out, or push-pull?

If you have heat-piped cards... (seriously), flip your case upside down. Heat-pipes are useless upside down. The vapor has to fight gravity, through the wick, and most of those setups blow the heat right back at the GPU it is trying to cool. Thus, just circulating hot air inside your case.

I suggest, if your PSU is Exhausting air... then only have one or two fans, near the bottom, to push fresh air inside. Only exhaust should come out the back, fresh from the front/bottom, near your GPU. If your GPU's don't exhaust out, then you might want to add one exhaust near the GPU/CPU area, to vent out the back, but keep the fresh air blowing directly at the GPU. Your CPU isn't doing much work anyways.

FYI: Good tip... Fill dead-space in your case with foam. The lower the air-space, the less "turbulance", and the more "flow" across the components. (That is what makes Blade-servers function so well. Air passes over everything and instantly exits, no swirling and lingering and circulating inside, retaining heat.) Not to mention the noise-deadening quality of foam. You can then use quieter fans too.

[Spendulus]

...
FYI: Good tip... Fill dead-space in your case with foam. The lower the air-space, the less "turbulance", and the more "flow" across the components. (That is what makes Blade-servers function so well. Air passes over everything and instantly exits, no swirling and lingering and circulating inside, retaining heat.) Not to mention the noise-deadening quality of foam. You can then use quieter fans too.

NO DO NOT DO THIS.

Foam if properly contoured for what is nothing but aerodynamics would improve air flow, but it should be obvious that that is not a simple matter of "filling the dead space with foam."  One error and everything over heats. 

tl;dr Gaming/Mining rig: Should I

• a) watercool 2 x Gigabyte 7970 Ghz WF, and apply heatsinks to the VRM/RAM; or
• b) swap for reference Diamond 7970 with full waterblocks?

Have updated my gaming rig to include 2 x Gigabyte 7970 Ghz edition cards - figured if I could get them mining, I may pay off the card cost within a few months (or at least get a few coins in my wallet).

Have a serious issue with cooling these.
They are in an Antec 900 case....
Thanks.

I also have 2 7970 in Antec 900 and I found heat problems (86C, 97C) went away when I took the side cover off, then laid the case on it's side.  Now mid 70s.  That's an absolutely HUGE difference and it tells me that somehow, in spite of those 5 fans blowing, these cards need their own consideration.  I am going to add 2 more cards and this requires riser cables.  Right now my opinion is that this can be made to look really cool.  We shall see.

[erk]

I am also having cooling problems with the Gigabyte 7970 Ghz version.  Mostly mining scrypt coins where you need to keep the mem clock up. I discovered that if you set the GPU engine clock to exactly 1000MHz the card will lower the voltage to 1.2v down from the default 1.256v which helps the cooling a bit.

I am looking at replacing the stock cooler with Arctic Cooling Accelero Xtreme 7970 kit. but I think I will try 2 x 120mm fans instead of the standard 3 x 92mm fans first and see if that makes any difference.

Open to any suggestions, the card is proving very tricky to cool.

[demosthenez]

I am also having cooling problems with the Gigabyte 7970 Ghz version.  Mostly mining scrypt coins where you need to keep the mem clock up. I discovered that if you set the GPU engine clock to exactly 1000MHz the card will lower the voltage to 1.2v down from the default 1.256v which helps the cooling a bit.

I am looking at replacing the stock cooler with Arctic Cooling Accelero Xtreme 7970 kit. but I think I will try 2 x 120mm fans instead of the standard 3 x 92mm fans first and see if that makes any difference.

Open to any suggestions, the card is proving very tricky to cool.

I ended up returning the Gigabyte cards and replacing them with reference Diamond cards. Worked out a good choice, saved $50 per card, they clock higher and are stable, and the turbine fan style vents all the hot air outside the case. Temps are good (low-mid 70's), but the stock turbine fans do get loud.

[computerparts]

I am also having cooling problems with the Gigabyte 7970 Ghz version.  Mostly mining scrypt coins where you need to keep the mem clock up. I discovered that if you set the GPU engine clock to exactly 1000MHz the card will lower the voltage to 1.2v down from the default 1.256v which helps the cooling a bit.

I am looking at replacing the stock cooler with Arctic Cooling Accelero Xtreme 7970 kit. but I think I will try 2 x 120mm fans instead of the standard 3 x 92mm fans first and see if that makes any difference.

Open to any suggestions, the card is proving very tricky to cool.

That's the problem with the rev.2 pcbs. The voltage is dynamic by the way so no surprise that it went from 1.25 to 1.2 but 1.2 is still wayyyyy too high. The Accelero Extreme will only be a band aid because it will still run hotter than it should. I'd send it back if possible and get a non ghz edition and make sure it's rev.1 if it's Gigabyte. Not directed at you but what's with all the thread necros today?   

[erk]

That's the problem with the rev.2 pcbs. The voltage is dynamic by the way so no surprise that it went from 1.25 to 1.2 but 1.2 is still wayyyyy too high. The Accelero Extreme will only be a band aid because it will still run hotter than it should. I'd send it back if possible and get a non ghz edition and make sure it's rev.1 if it's Gigabyte. Not directed at you but what's with all the thread necros today?   

Is there a firmware I can use to get the voltage down a bit more?